Simple Question: What is the function of the EZL? I am not familiar with the 103 engine, and I am trying to help a friend fix her car..the Mercedes shop says the hesitation in the engine is due to a worn out EZL ...

Also, anyone know what the part number for the EZL would be? 1991 300e is the car

This is just a regular 91 300E. I don't know about your neck of the woods but out here these cars are showing up in the U-Pull-It yards in big numbers now. There's no reason to pay very much and there is no reason to deal with the operators on KnappyBay or those thieves at the stealership.
Regards, Eric

Wouldn't hooking the car up to the SDS (or whatever it's called these days) pintpoint the issue fairly quickly, and be a lot less expensive than re-building the motor one part at a time? Tell me that the shop that did all the work wasn't Steve B's place!

__________________1988 California version 260E (W124)Anthracite Grey/PalominoOwned since new and still going strong and smoothMBCA member

Wouldn't hooking the car up to the SDS (or whatever it's called these days) pintpoint the issue fairly quickly, and be a lot less expensive than re-building the motor one part at a time? Tell me that the shop that did all the work wasn't Steve B's place!

They had it hooked up to their diagnostic devices (if that was what you were referring to)....the car had a dead computer, and that gave the tech a hard time i think....

This is just a regular 91 300E. I don't know about your neck of the woods but out here these cars are showing up in the U-Pull-It yards in big numbers now. There's no reason to pay very much and there is no reason to deal with the operators on KnappyBay or those thieves at the stealership.
Regards, Eric

Any idea if the EZL is a an item that wears out gradually causing performance degradation? or is it just either working or broken? I will be looking for a used one if anyone confirms this point....i can find them online for $40ish.....

Any frail electrical connection can be impacted by temperature, humidity, vibration, etc. The EPC says either 008 545 96 32 or 009 545 80 32 will work. Only 96 32 is still available from dealer, $1,000 list, $690 at parts.com.

latief, not sure about the internals of a 103 EZL, but those of a 104 EZL are epoxied which prevents the remanufacturers from identifying the internal components for potential reconditioning purposes. A few years ago used 103 EZL's were readily available from salvage yards, and cost around $40.

From my experience with a failed 104 EZL I would say they are either good or bad ... no in between stage. In your position I would recommend buying a used EZL once you verify that is indeed the problem. A local MB dealer diagnosed the bad 104 EZL quickly. In my case the engine suddenly would not start after eating lunch at a restaurant.

They either work or don't usually. BUT what can happen is they will cut out on you, so might work for awhile, then make the car stall. Now, when they act this way, they will usually stop working under high underhood temps, so this time of year is when you can see the problem.

Any idea if the EZL is a an item that wears out gradually causing performance degradation? or is it just either working or broken? I will be looking for a used one if anyone confirms this point....i can find them online for $40ish.....

I know this is often the case with the CIS-E ECUs and I've also seen this same phenomenon with coils but I'm not sure about the EZLs. Haven't had or even seen a bad one yet! I don't think they go bad very often.

One thing I am sure about though is that you can often times fix a "bad" part by just unplugging and then replugging the connections on that part. Actually, the same is true for just about every electrical thing on a 20 year old car. I firmly believe that half the time, when a "new" part "fixes" a problem, it was really just the disconnecting and then reconnecting of the plugs thus re-establishing the electrical connections that was really the cure but the "new" part gets the credit.

And if you really do need another one, go to the U-Pull-Its, save some money, and actually see and choose which donor car you want to get your parts from. More peace of mind that way. Stay away from the full service yards.
Regards, Eric